It was an unlikely fashion accessory but the arrival of a jewel-encrusted beetle at a US border post certainly bugged customs officers.

A woman crossing from Mexico at Brownsville, Texas, declared the live insect decorated with blue and gold as she drove up to enter the state but she did not have the right paperwork.

Pest control measures meant officers promptly confiscated the item worn as a brooch on the traveller's sweater and sent it for further inspection. The beetle was attached to the woman's clothing by a gold chain and safety pin.

The story of how the six-legged fashion victim was intercepted came in a press release and video from US Customs and Border Protection (CBP), part of the security machine responsible for protecting the country from terrorists and a body more used to trumpeting the seizure of cocaine, marijuana, hidden cash or fugitives from justice.

"CBP officers seized the decorative clothing accessory and sent the live beetle to the Plant Inspection Station at Los Indios International Bridge for further identification. Because the traveller declared the insect no monetary civil penalty was issued," the official account declared.

"Moving live plant pests in any form, including pets, imported into or exported from the United States must be declared to CBP on PPQ form 526 declaration for importation or exportation, must be properly labelled and packaged prior to release by CBP."

Animal rights campaigners were less forgiving, reported the south Texan newspaper The Monitor.. Jaime Zalac, for People for the Ethical Treatment of Animals,said: "Beetles may not be as cute and cuddly as puppies and kittens, but they have the same capacity to feel pain and suffer. It's ironic. We spend hours each week helping kind people find humane ways to relocate lost insects such as ants, bees and roaches that wander into their homes. People feel so good about not hurting them, while this woman paid someone to mutilate them."

Beetle species have proved popular subjects for jewellery for centuries and attaching it to live beetles is apparently not uncommon in Mexico. Jackie Kennedy is said to have been given one with emeralds.